I did a local TV series YEARS ago on using arrangers for composing. ("Perspectives" in Philly) It's kind of ironic, because I hardly EVER write! I know too many songs, and every time I think I have a great, new idea ... it turns out to be someone else's poetry or melody. Sigh ... cost of doing business. The show was kind of cool though, for it's time. It was in the infancy of "good" arrangers ... when competition really raised the bar from the cheesy Casio stuff of old. The biggest advantage, that I showcased was the ability to change rhythms and styles with the same basic chords and melody. Kind of a "fresh" idea machine.